How to use Flask-Script and Gunicorn

Question

I\'m working on on a Flask app using Flask\'s built in dev server. I start it using Flask-Script. I want to switch to using Gunicorn as the web server. To do so, do I nee

Answer 1

I wrote a better version of GunicornServer based on Sean Lynch's, the command now accept all gunicorn's arguments

from yourapp import app
from flask.ext.script import Manager, Command, Option

class GunicornServer(Command):
    """Run the app within Gunicorn"""

    def get_options(self):
        from gunicorn.config import make_settings

        settings = make_settings()
        options = (
            Option(*klass.cli, action=klass.action)
            for setting, klass in settings.iteritems() if klass.cli
        )
        return options

    def run(self, *args, **kwargs):
        from gunicorn.app.wsgiapp import WSGIApplication

        app = WSGIApplication()
        app.app_uri = 'manage:app'
        return app.run()

manager = Manager(app)
manager.add_command("gunicorn", GunicornServer())

Answer 2

Flask actually has docs to run Gunicorn here.

You have to remember that Gunicorn is a WSGI server with some niceties.

Answer 3

Thanks to @menghan's solution and @OutOfFoodException improvement. But remember that for gunicorn=20.0.4 for binding server socket using -b, --bind option. And result command for me was like that:

python3 manage.py gunicorn -b 0.0.0.0:5000

from yourapp import app
from flask.ext.script import Manager, Command, Option

class GunicornServer(Command):
    """Run the app within Gunicorn"""

    def get_options(self):
        from gunicorn.config import make_settings

        settings = make_settings()
        options = (
            Option(*klass.cli, action=klass.action)
            for setting, klass in settings.iteritems() if klass.cli
        )
        return options

    def run(self, *args, **kwargs):
        from gunicorn.app.wsgiapp import WSGIApplication

        app = WSGIApplication()
        app.app_uri = 'manage:app'
        return app.run()

manager = Manager(app)
manager.add_command("gunicorn", GunicornServer())

Answer 4

Based the answer of the Sean, I also wrote a version more preferred to me.

@manager.option('-h', '--host', dest='host', default='127.0.0.1')
@manager.option('-p', '--port', dest='port', type=int, default=6969)
@manager.option('-w', '--workers', dest='workers', type=int, default=3)
def gunicorn(host, port, workers):
    """Start the Server with Gunicorn"""
    from gunicorn.app.base import Application

    class FlaskApplication(Application):
        def init(self, parser, opts, args):
            return {
                'bind': '{0}:{1}'.format(host, port),
                'workers': workers
            }

        def load(self):
            return app

    application = FlaskApplication()
    return application.run()

you can run the gunicorn using command like thispython manager.py gunicorn

Answer 5

Based on menghan's answer, receive all arguments from Application config.

from flask_script import Command, Option


class GunicornApp(Command):

    def get_options(self):
        from gunicorn.config import make_settings

        settings = make_settings()
        options = (
            Option(*klass.cli, dest=klass.name, default=klass.default)
            for setting, klass in settings.items() if klass.cli
        )
        return options

    def __call__(self, app=None, *args, **kwargs):

        from gunicorn.app.base import Application
        class FlaskApplication(Application):
            def init(self, parser, opts, args):
                return kwargs

            def load(self):
                return app

        FlaskApplication().run()

Answer 6

I will elaborate further on the answer by @NinjaDQ. If you want to use app_uri attribute for defining for example the flask application configuration file and custom command line arguments at the same time, you need to use WSGIApplication. The problem is that this application overrides the command line arguments thus it is necessary to ignore the sys.argv.

        from gunicorn.app.base import Application

        class FlaskApplication(Application):
            def init(self, parser, opts, args):
                return {
                    "bind": "{0}:{1}".format(host, port),
                    "workers": 4
                }

            def chdir(self):
                # chdir to the configured path before loading,
                # default is the current dir
                os.chdir(self.cfg.chdir)

                # add the path to sys.path
                sys.path.insert(0, self.cfg.chdir)

            def load_wsgiapp(self):
                self.chdir()

                # load the app
                return util.import_app(self.app_uri)

            def load(self):
                return self.load_wsgiapp()

        # Important! Do not pass any cmd line arguments to gunicorn
        sys.argv = sys.argv[:2]

        wsgi_app = FlaskApplication()
        wsgi_app.app_uri = "manage:create_app('{0}')".format(config_file)

        return wsgi_app.run()